What makes a place the ideal spot for retirement -- and what makes other places a potential disaster for retirees?

There are several personal choices that make some places more attractive than others -- where your children and grandchildren live is probably at the top. But there are some more objective and measurable factors that determine whether a state is a good or a bad place for retirees. The following are the factors used to determine the ten best and worst states for retirement:

Economic factors. Using a combination of cost of living in major metropolitan areas, unemployment and tax burden, rated the states from best to worst according to economic conditions.

Climate. Americans tend to set the thermostat at around 68 degrees. So, used this as the standard, and rated states according to how far their monthly temperatures varied from 68 degrees.

Crime rate. Security is a particular concern for senior citizens, so violent and property crime rates were used to rank the safety of the state.

Life expectancy. States conducive to long lives are naturally well-suited for retirees.

For frequently updated data, such as unemployment, the most recently available monthly figures were used, whereas for other criteria that reflect longer-term trends, such as climate, more historical information was used.

Based on the criteria stated above, the following are the ten worst states for retirement, with No. 1 being the worst. Since just about every state has at least something going for it, we highlight both the good and the bad, so you can decide which factors would matter most to you.

No. 10: Arkansas

Economic factors: Cost of living is 90 percent of the national average, unemployment is at 7.4 percent, and the average state and local tax burden is 10 percent.

Climate: Average monthly temperatures range from 38.4 degrees in January to 80.57 degrees in July.

Crime rate: 12th in the nation in violent crime, and 11th in property crime.

Life expectancy: 75.2 years.

Reason for low rank: Unemployment isn't bad, the climate is good and the cost of living is excellent. However, Arkansas is done in by relatively high crime rates and tax burdens, and life expectancy is the eighth-worst in the nation.

No. 9: Missouri

Economic factors: Cost of living is 91 percent of the national average, unemployment is at 9.2 percent, and the average state and local tax burden is 9.2 percent.

Climate: Average monthly temperatures range from 28.83 degrees in January to 77.54 degrees in July.

Crime rate: 15th in the nation in violent crime, and 14th in property crime.

Life expectancy: 75.9 years.

Reason for low rank: Except for a low cost of living, Missouri doesn't stand out in any category, but a relatively high crime rate and a relatively low life expectancy make it a somewhat unwelcoming environment for retirees.

No. 8: North Carolina

Economic factors: Cost of living is 97 percent of the national average, unemployment is at 9.8 percent, and the average state and local tax burden is 9.8 percent.

Climate: Average monthly temperatures range from 39.97 degrees in January to 77.49 degrees in July.

Crime rate: 19th in the nation in violent crime, and 7th in property crime.

Life expectancy: 75.8 years.

Reason for low rank:The climate is very temperate, but North Carolina rates poorly on the basis of crime rate, unemployment and life expectancy.

No. 7: Ohio

Economic factors: Cost of living is 93 percent of the national average, unemployment is at 10.3 percent, and the average state and local tax burden is 10.4 percent.

Climate: Average monthly temperatures range from 26.5 degrees in January to 72.78 degrees in July.

Crime rate: 26th in the nation in violent crime, and 20th in property crime.

Life expectancy: 76.2 years.

Reason for low rank:Ohio is fairly average on most criteria, but both the unemployment rate and the tax burden are in the double-digits.

No. 6: Tennessee

Economic factors: Cost of living is 89 percent of the national average, unemployment is at 9.8 percent, and the average state and local tax burden is 8.3 percent.

Climate: Average monthly temperatures range from 36.32 degrees in January to 77.29 degrees in July.

Crime rate: 2nd in the nation in violent crime, and 6th in property crime.

Life expectancy: 75.1 years.

Reason for low rank: Tennessee is a cheap place to live, with a low cost of living and average tax burden, but this doesn't make up for being one of the worst states for crime and life expectancy.

No. 5: Maryland

Economic factors: Cost of living is 126 percent of the national average, unemployment is at 7.1 percent, and the average state and local tax burden is 10.8 percent.

Climate: Average monthly temperatures range from 32.24 degrees in January to 75.44 degrees in July.

Crime rate: 9th in the nation in violent crime, and 21st in property crime.

Life expectancy: 76.3 years.

Reason for low rank:Between the cost of living and the tax burden, Maryland is expensive, and the high rate of violent crime is also troubling.

No. 4: South Carolina

Economic factors: Cost of living is 97 percent of the national average, unemployment is at 10.8 percent, and the average state and local tax burden is 8.8 percent.

Climate: Average monthly temperatures range from 44.12 degrees in January to 80.08 degrees in July.

Crime rate: 1st in the nation in violent crime, and 2nd in property crime.

Life expectancy: 74.8 years.

Reason for low rank:You can find things to like in South Carolina -- the pleasant climate, for example -- but the high crime rates would be enough to scare off many retirees, and the life expectancy (one of the lowest in the nation) is a downside.

No. 3: Alaska

Economic factors: Cost of living is 128 percent of the national average, unemployment is at 7.7 percent, and the average state and local tax burden is 6.4 percent.

Climate: Average monthly temperatures range from 16.5 degrees in January to 59.0 degrees in July.

Crime rate: 8th in the nation in violent crime, and 23rd in property crime.

Life expectancy: 77.1 years.

Reason for low rank:The nation's lowest tax burden is more than offset by the high cost of living, and the harsh climate and high rate of violent crime are not friendly to retirees.

No. 2: Michigan

Economic factors: Cost of living is 97 percent of the national average, unemployment is at 13.1 percent, and the average state and local tax burden is 9.4 percent.

Climate: Average monthly temperatures range from 18.87 degrees in January to 68.32 degrees in July.

Crime rate: 10th in the nation in violent crime, and 27th in property crime.

Life expectancy: 76.3 years.

Reason for low rank: The high unemployment rate is indicative of a severely damaged economy, the climate is a little rough, and the violent crime rate is a concern.

No. 1: Nevada

Economic factors: Cost of living is 105 percent of the national average, unemployment is at 14.3 percent, and the average state and local tax burden is 6.6 percent.

Climate: Average monthly temperatures range from 30.43 degrees in January to 71.94 degrees in July.

Crime rate: 3rd in the nation in violent crime, and 13th in property crime.

Life expectancy: 75.8 years.

Reason for low rank: Nevada has the second lowest tax rate in the country, but scored poorly on just about every other criterion. Gambling enthusiasts may disagree, but high crime rates and a dismal economy make Nevada a bad bet for retirees.